A window blind or curtain is generally opened or closed by the use of a cord or chain, which may dangle within reach of young children and present a safety hazard. As well, a freely dangling cord can become tangled, and is seen by some as unsightly and cumbersome to operate. Various solutions have been proposed to address this problem. In particular, the present inventor has been granted U.S. Pat. No. 5,279,473, and has filed application no. 08/022,891, relating to a take-up reel to retract the cord of a window blind, and in particular, the cord loop of a vertical blind. As well, the present inventor has filed application no. [application number not yet assigned], relating to a wand for the taking up of the cord of a horizontal slat-type venetian blind.
The cords of vertical blinds and certain roller blinds, curtains and other window coverings are particularly difficult to retract, since these typically comprise a cord loop that must be cycled in one direction or the other to open or close the covering. There exist a variety of window coverings that are operated by a cord loop; it will be understood that the term "blind" as used herein refers generally to any type of window covering that is operated by the cycling of a cord loop through a headrail. In the case of a vertical blind, the cycling of the cord loop displaces the vanes laterally to open or close the blind. Typically, the cord loop extends through the headrail of the blind, and is linked to a lead vane carrier or carriers. An end of the loop dangles from the head rail to permit user actuation of the blind. For reference purposes, this dangling portion of the loop will be arbitrarily described as comprised of first and second strands, with the first and second strands comprising the two vertical strands of the same cord loop. A downward pull of the first strand draws the blind open, and a downward pull of the second strand draws it closed. Similarly, other types of blinds may be provided with a cord loop that serves a similar function.
Difficulties are encountered if it is desired to retract a portion of the loop to take it out of reach of children. An ordinary take-up reel engaged %o the cord would prevent it from freely cycling in both directions. As well, a take-up reel, even if adapted to allow the cord to cycle freely, suffers the drawback of requiring the user to operate the reel to draw up the cord after each use. If this step is not taken when a young child is present, tragedy may result.
It is desirable to provide a device that partly or fully encloses the cord loop at all times, but still permits a user to drive the cord loop. The use of an enclosure avoids the use of a freely dangling cord loop or the active step of retracting the cord after each use.
As well, for purposes of aesthetics and convenience, it is desirable to integrate the lateral vane opening means of a vertical blind with a means for rotating the vanes of the blind. Typically, a vertical blind is provided with a rotatable "tilt rod" journalled within the interior of the headrail, linked to an array of vane carriers slideably disposed within the headrail. The vane carriers are adapted to translate rotational movement of the tilt rod into rotation of the vanes. One end of the tilt rod terminates in a sprocket, and the user rotates the tilt rod by cycling a chain depending from the sprocket. This vane-rotation chain represents an additional hazard and inconvenience, and may be replaced by a tilt rod drive means, comprising a rotatable shaft, linked to the tilt rod by means of a universal joint or the like and a gearing system, wherein rotation of the control rod is translated into rotation of the tilt rod. The control rod may be integrated with blind-opening means to provide a single unit to control both rotation and lateral displacement of the vanes.